Precision oncology specialist Guardant Health (GH 8.53%) was something of a stock market star on Tuesday. On the back of very positive news in the regulatory sphere, the company's shares jumped almost 9% higher today. This made it quite the outperformer on the exchange, as the bellwether S&P 500 index's gain was a relatively modest 0.6%.A new designationThis morning before market open, Guardant announced that the U.S. Food and Drug Administration (FDA) had granted the healthcare company's Shield multi-cance ...